Stacey_Guide_7 - (7) Study Guide-Ch. 3- Plate...

Ch. 3- Plate Tectonics (1-6-08) Sections 3.5, 3.6*, 3.3^ * not including subsection “Terrains” ^now discussing subsection “Polar Wandering Curve” 1)Explain the difference between “passive” and “active” continental margins.-passive : (trailing) closest to ocean ridge -slowly subsides -eroded by ocean waves and currents -accumulates substantial sediment deposits -active : (leading) edge of the overriding plate of a subduction zone -narrow/steep -accompanied by uplift and folding of land along it 2)Is the “motion of plates” theory accepted by all geologists? -Yes, it is accepted, for the most part. Why or why not? - details are still unclear, poorly explained, and remains controversial -the plate motions do seem to be connected with convective motions of molten magma in the asthenosphere 3)What is the average rate of motion of the plates? -1-20 cm/yr How is the motion measured? -GPS

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